Marseille, who travel to Dutch side Twente Enschede for a UEFA Cup last-32 second leg tie on Thursday, allowed Lyon to open a six-point gap over Paris St Germain at the top after labouring to a goalless draw against lowly Le Mans last weekend.
"It will not help to cry over this," coach Eric Gerets told the club's website. "We missed an opportunity but ... it is not over.
"We are not dead yet. There was a time we were able to make forays into any defence. It has been a bit more difficult lately but it will come back."
Third-placed Marseille can exert pressure on the leaders before Lyon's home game against Stade Rennes, a team they have not beaten in the league at the Gerland stadium in the last three years, later on Sunday.
Brazilian defender Ceara said the league was PSG's priority.
"Our first goal is the league and we will do whatever it takes to at least stay second," he said.
